Introductory Biology Practice Problems 3a through 3j, and 4a through 4c (and their solutions) cover the concentrations of ions and types of channels responsible for the resting potential, channel permeability and ion movement during the action potential, resting potential and how it is maintained in a neuron, and states of various channels during an action potential and the effect of defective mutant channels on the shape of an action potential.

Introductory Biology Practice Problem 3 and Problems 4a through 4i (and their solutions) cover cells that contain MHCI and MHCII and the peptides presented by the MHC molecules,a quantitative calculation of the result of VDJ recombination that creates antibodies, and B and T cell receptors, and the fate of immature and mature T cells that recognize foreign and self antigens.

Introductory Biology Practice Problems A through C (and their solutions) cover different parts of a gene encoding an antibody showing variation produced by VDJ DNA rearrangement and alternative splicing,cells and molecules involved in an immune response to viral infection, and biochemical interactions between antibody and antigen, and DNA mutations that strengthen or weaken these interactions.